Note: Descriptions are shown in the official language in which they were submitted.
" ll~;J'~9S9
FIELD OF IN~ENTT~r
Thia invent~on relate~ to a range controller for cont$nuously
monitoring the posltion o~ ths boom ot he-vy ~achineri~ uch a-
excavators and cranes.
~ACKGROUND Of INVEN~ION
When a contraotor has to perform constructioh, exc-v-tion
or other t~pes of work on a~~~lte~ he u~ea variety ot heavy n-chlnery
Amongst such machinary, some are us-d for excavation work, oth-r to h
move loads up and do~n and from oQe location to another. Th~ echines
are e~uipped with booma or mobile arma having ometime- ubet-ntlal
operating range The mobility and the extent of ths dlsplaoq~ent ot
the boom of these machlnes are lmportant tools for performlng the workt
but it i9 al80 a great danger for the ~orkera and the vsrioua ob-tacles
present within the op~rating range ot the machlnes. Accldenta~ uhlch
are not only moterially costly but alao caus- ma~or lniurle- to the
workers or ev n lo~e of lives, o~ten hsppen. For exa~ple, upportlng
columns are o-ten knocked down by the boom of a crane. ~hen worklng
close to power lines, there is an ever-present danger fron the boom
to come in contact with the po~er llnes and often cauae the de-th of
the operator or other uorkers on the slte The latter la p-rticularly
important due to the lncreaslng nu~ber of power llne~ no~ ~ou~,d on
working sites. In ~ome are-~ it 1~ forbldden by lau to ~ork wlth~n
e epecific dlstsnce from power linea
Since human error 1~ the maln caù~e of all accld~nts, ~arloua
systems have been proposed to detect excessive displace~ent of the
boom of e heavy machinery or the purpo~e of avoidlng nverlDadlng
or striking of obstacles. Applicants o- the present applicatlon have
al80 disclosed in U.S. Patent No. 4,236,a64 dated Oeoemb~er 2, 1900
a "SAfETY CONTROL SYSTE~ FOR THE ~00~ OF A CRANE". How ver, the
known system3 ere mostly elertrc-mechanical ln nature and, thua, lack
versatility.
OOJECT ~F INUENTION
It i8 therefore the ob~ect of the present invsntlon to prouide
~C
~ 2
t , ;11'7'~959
,,;
a range controller which uses an electronic control ~ystem to con-
tinuou~ly monitor the actusl-position Or the boom ot heavy machinery
with respect to surrounding obstaclee snd to provide a ignal ~hen
the boom is approeching any such obstecles and even block the operation
of tha boom ~h0n it is w$thin_a critical dlstence from auch obstecle.
Su~
The r~lga cnntroller in accordance with the invention com-
prises position sensoro mounted on the boom and on the machlnery for
continuously detecting the spatial position of the boom with re~psct to a
reference~ control owltche~ located in the c-bin Or the machinery
for permitting the operator to set the position limite of th- boom~
a central control circuit mounted on the maohinery and compriaing a
micro-processor circuit edopted for connectlon to the sen~crs 0nd to
the control switches and memory de~iceo for regi~ering the position
of the boom as well as the position limito set by the op6rotor anC
for continuously comparing the ~ctual poeition nr th~ boom with the
posit~on limits~ and indicators located ln the ca~in of the ~aa~iinery
and responsive to such micro-proceosor circuit for warnlng the
operetor and, preferably~ block the operation Or the boom when o
position Iimit is reached.
The pooitlrn aen-or~ preferably comprls~ a vertlcal po-ltion
sensor capable Or detectlng and tran~lating the angle o~ the Ooo~
into an electronic signal readable by the mlcro-procee-or clrcult, and
e horlzontal posltion sensor capable Or ~enelng the relatlv- po-ition
of the machlne with respect to the horizontal and ot translating uoh
position into an electronic signsl readable by the mlcro-prooeesor
circuit.
When the machlnery is a telescopic crane, a teleecoplc poe~tion
sensor may also be poeitioned on the m-chinery and ~dapted to tran-l-t-
the boom lsngth dif~erential posltlon lnto an electronlc ~ignal r0adable
by the micro-processor circult.
When the ma~hinery is a towar crana, a sansor is providad to
~etect the position of the trolley travalling on the swinging trolley
supporting horizontal boom.
. ~ , . ..
, . -- ,, _
li~7'~59
A ~isplacoment sensor may also be provided t~ u~t~ct any
displac~m~nt nf th~ machinery on the ground.
Exterior in~icators may also ba mounted on the top of the
machinery for warning people outside of the cabin of the m~chinery
of t~e po;sibl~ danger.
In a preferred embodiment of ths invention, the central control
circuit comprises an input multi-plexer circuit connected to the position
and displacement ssnsors and to the control switche~ in the cabin to
channal all input data from the sen~ors and the control switches to
tha micro-processor circuit~ and an output circuit connected to the
inaicators lncated in the cabin, to the exterior indicators and to
the blocking system to latch output dats and drive auch indicators
and the blocking system following the data provided by the micro-
proce~sor circuit,
A failure detector circuit is also preferably provided in
the central control circuit for detecting failure of the micro-
processor.
Data switches are also preferably provided in the central
control circuit and adapted to be programmed at the time of installation
of tha contrpller to insert in the micro-proces~or circuit data that
ars pertinent to the type of machinery it i8 adapted to be used on.
~RIEF DESCRIPTION OF THE DRAWINCS
The inv~ntion will now be disclosed~ by WAy of example~ with
reference to the accompanying drawings~ in which~
Figure 1 is a block diagram of a range controller in ac-
cordance with the inuention;
Figure 2 illustrates schematically the uarious elements of
the block diagram of Figure 1 installed on an excavator;
Figure 3 is a block diagram of the control box;
~0 Figure 4 is a block diagram of a vertic~l position sensor;
Figurs 5 illustrates an embodiment of a position sen~or
in accordance with the invention;
Figurs 6 i9 a block diagr~m of a horizontal position sensor~
Figure 7 illustrates an embodiment of a horizontal position
'7959
.,
n~10r in accaro~nc~ l~ith th0 invention;
Figure ~ i~ a gchemRtlc diagram of the central control
clrc:uit;
Figur0 9 1~ a achsmatic diagram of ths input multi-plexer
of the central control circuit;
Fi9UrH 10 i9 a sch~metlc diagram of the output circuit of
the central control circult; and
Fi~ure 11 19 a ~chsmatic diagrQm of the failure detector.
D~TAiLFD ~SCRI~T20N Of IN~ENTInN
figurn l of th~ dr~wing~ illustrates A ~neral block diagram
o~ a ran~s controll~r in accordancs with the invontlnn, while Figure 2
illu~trAt~s th~ locatinn of the variou~ componsnt~ of the cnntroller on
a conventlonal excMvator ~ a9 a 9imple Bxample of an embodlment af the
invention. The ~xcavator ic equlpped wlth R main boom 10 which pi~ots
in el0v~tlon on the frame of the excavator and heel boom 12, which ~8
articulat~d on the outer ~nd of the main boom. The boom of the excevator
al~o ~win99 ho~i70ntally on e turn^tsbl0 14 mount~d on a tractor unit
16. A cabin 18 i9 mount0d on the frame of the excavator.
The ranye controll0r comprisss a junction box 20 includin~ a
micro-processor hased control circuit, which i~ mountt3d lnaide the
cabin 18 at a suitable location, pref~rably at th~ back of the operator
seat. A control box 22, lncluding indicetors and control cwitche~, a8
iS will be di~clo~ed later, i~ cnnnected to the jLInction box and ln8talled
in the cabin wlthin reAch of th~ operator. A vertlcal po~ition sensor 24
i9 installed on the maln boom 10 and on the he01 boom 12 of the machine.
A horizontal poeition s0nsor 26 is installed on the rotating sygtem
of the machine `ey m0ans of a proper ~oupling (not ~hown). ~ertical and
horizontal position sensor~ 24 and 26 ar0 devlc6s capabla of transletlng
the angle of th0 boom and ths r01stlve horizont~l position oP the
~0 ~lachins, re6pectlvsly, ~nto ~l~ctronlc ~i~nals rsad~ble by the aont~ol
circuit in ths junction box 20. A tsleecopic poaition sensor 28 may be
u~ed on t01s~copic crans~. Such ~ sflnsor would translat~ th~ boom
length differential po~ition into an ~lectronic ~igral re~dable by the
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llt7'7959
cl3ntrul circuit iu th~ junction bo~ ~!. Su~h a sensor would be inst~lled
nn t~lL~ boom of th~ crane. ~ displacum~nt ssnsor ~SO~ which may be a
pr~s~ur~ ~witch nr a micro-~wltch, is also connectoo to th~ junction
box 20. ThH dis.plQcemHnt sensor is used ~o ~l~tect if the machine changea
itc; position on ttl~ groun~ and is in~tall~d at th~ most proper placu
in the machin0 traction system~
For a tower crane, horizontal position sensor 26 is installed
on the rotating system of the swinging trolley supporting horizontal boom,
whi~ sensor 24 is rsplac~d by a s~nsor detoctin~ th~ position of th~
lù trollay along th~ boom~ All other characterictics o~ thc syst~m rsmain
th~ same.
The output of ssnsors 24, 26, 28 and 30 aro all connected
to the junction l~ox by suitable cabla connactions. A blocking system 32,
which may consist of valves or othsr m~chanical d~vic~s, ~epandillg on
tho typo of machine, is conn~ctcd to ths output of tha ~junction pox.
The blocl<ing sy3tam is controlled by a SHt of relays in ths junction box.
It is installed at c prop~r placs to assurs blocking of the manoeuvers
of the machine. An exterior indicator~ ~uch a~ light 34, i9 install~d
on the top of the cabin. An audible alarm, such as buzzer 36 (Figure 1)~
2a can also bs installed to warn people outslde of the cabin of a possible
dangur. Powur is provided to the junction box by the machine battery
3~, or any other sui~a~)lH sourcs of supply~
Fi~urs 3 ls a block diagram oY ths control box ~0, mentioned
previously. Ihis t,ox contaln3 ths followinq control switchos Por the
operation Or the system;
a) a selactor ~witch Sl, which is usfld to ohooss the mode
of operation and to program the position limits of th~
boom, as it will ba djsclosed latHr;
b~ a main switch S2, which i9 used to put the power on;
3U c) a ~anual modu override switch S3, which is u~d by the
fo~eman,for example tu insui~H that the operator will
~eally use the systom and progra~ limits; and
d) a retllrn ~witcll S4, which i~ usud to com~ back in the
work zone wt,on th~ mano~uv~rs havn been blocked by
thu blocking system ~2.
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117'79S9
Thn control box al90 contains visual and audible indicatorq
that w.ill inform the op~rator iF the machins is in its work zone (green
light Ll), its warning zone (yellow light L2 flashing and buzzer A
beeping), or its forbidden zone (r~d light ~3 and buzzer A). Also, if
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llt~.7~59
failure occur~, th~ proper indic~ltion~ will warn the operator. All
these indicatnrs and ~witcheg are wired on a cable 40 for connection to
the junction hox 20.
Fi~ re 4 is a schematic dlagram of the vertical pogition
sen~or 24. Thi~ module i8 install~d on the boom of ths machine, in
a c~rtsin po~ition. It contains a ~et of light-emitting diodeg Dl~ D2,
and 03 facing photo-transistor detector~ Tl, T2, and T3, respectively.
The output~ of the photo-transistor detectors Tl, T2, and T3 nre then
amplified by Amplifiers Al, A2, and A3, respectively~before b~ing fed
to the junction box as an input to cable 42. The diodes are energized
from the battery ~upply of the junction box through resistor Rl.
A structural embOdiment of a detector unit is shown in figure
5 of the drawings. The embodiment co~prise3 a base plate 44, which i8
secured to the boom o~ the excsvAtor. Diodes 01, 02~ and D3 are mounted
on circuit board 46 and photo-transistor detectors Tl, T2, and T3 are
mounted on circuit board 48. Mounted between the two circuit boards
46 and 4~ i~ a transpHrent casing 50 into which i8 mounted a plate 52
which i8 adapted to rotate freely on a central axle 54. One-half of
the plate 52 i9 mede heavier than the other by the addition of a ~eight
56, ~o that the plate will always stay in the same position with regard
t~ the horizontal. However, the circuit bosrds 46 and 48 sre fixed
to the base plate 44, 80 that there is relative movement betueen the
optic couplflrs (Dl-Tl, 02-T2~ etc.) and the plate 52 when the boom of
the machine i8 moved with respect to the vertical. A coded screen~
illustrated sch0matically by reference numeral 58, is placed on
the plate 52. In a preferred embodiment of the invention, this coded
screen has three rows of opa~ue and transparent spots that will interfere
with the path of the light between the light-emitting diodes Dl, D2
or D3 and the photo-tran~istors Tl, T2 or T3, respectively, 80 that the
photo-transistors will give output signals that can be translated into
the engle of the boom with respect to the horizontal. Of course, any
type of coding system cspaole of tran~lating the angle of the boom into
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11'7'~'35g
an elictronic si~Jnal readable by the micro-proce~eor, can be u~ed.
The cafling 50 i9 pref~ra~ly ~llled with oll to allow dampening et the
plflte 52 during movement of the boom. A cover 60 i9 providsd for ,'
enclosing the horlzontal sensor.
Figure 6 i~ R circult dlagrAm of the hori~ontsl position sensor
26. This modul~ contains a eet of light-emittlng dlodee D4, D5, and Dfi
facing photo-transistor detectors T4, T5~ ~nd T6~ rnspectively. The
output of the photo-transistor detectors i~ ~nd to th~ ~unction box ae an
lnput through cable 62. The diode~ are energlznd from the battery supply ,~
of the ~unctianbox through re~istor R2. The ~onstruction of the
horizontal seneor le the ~ame as the vertical sen~or, shown ln Figure 5~ ,
except that tho plate 52 hes no welght ~nd that tha axle 54 o~ plato 52 P
ia coupled -to,the 3ha~t 64 of tbe mHchlne swlng motor, ~8 shown in rigure
7.
A code~ ecreen 1~ also put on the rotAting plate 52,as for
the vertical sennoi~s; thi~ will lnter~ere in the light path of the
optic couplsr~ trl generate at the output of the photo-tran~ietors a
signal th~t can be translated into the horl20nt~1 po~ition bf the
machine with reapect to fl reterence.
Thh tnlescopic posltlon flen~or may be ldentlcal to the
horlzontal po~ltlon ~en~or. However, inste~d of bein~ couplod to th
swln~ motor, the shaft is coupled to a wlnch that will rotate when
the l~ngth of the boom changes.
FiQure B ie a block di~gr~m of ths ~unction box. It contAins
the central control circuit and ~11 the nece6sary components to connect
to ~11 thn modules o~ th0 control',er. As thls control circuit iQ mlcro-
proces~or-bAeed, almost all the Punctions o~ the oontrol circult are
executed by the ~oftware and these ~unctlons will be ~n~ly2ed later ln
th~ softw~re dr~cription.
The ~onS;rol circuit 1~ made of the follow~ng lnterrelated
circuits:
a) ~ micro-proces~or circult 65 whlch cont.rols e~erythlng~ ~he
program (so~tware) le stored ln a read-enly-m~mory ~R0~ 66
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11~7'7959
containing all the instruction~ that will be executed
sequflntially by the micro-processor circuit, a9 it is commonly
known in the art. A random access memory (RA~) 6~ i9 connected
to ths micro-processor circuit to store data and for inter-
mediate calculations, as al~o commonly known in the art. The
operation of the micro-processor i~ synchronized by a clock 70;
b) an input multi-plexer circuit 72, which i8 uaed to channel
all input date from the control switches in the control box 22
and from the sensors 24, 26~ 2E~, and 30 to the micro-processor
circuit. The input multi-plexer i9 controlled oy the micro-
processor circuit. A more detailed descrlption of the input
multi-plexer circuit will follow;
c) an output circuit 74~ which is used to latch output data and
drive the blocking ~ystem 32, the control box indicators and the
external indicctors 34 and 36~ following the data provided by the
micro-proces~or circuit. The output circuit is al80 controlled
by the micro-processor. A more detailed description of the
output c~rcult will follow;
d) a failure detector circuit 76, which is used to detect a ~ailure
of the micro-proce3sor. A mors detailed description of the
failure deteetor circuit will follow;
e) an euxiliary clrcult 78, which provides the necessary reset circuit
to initiate the operation of the micro-processor. The auxiliary
circuit also contains an e~table circuit to make the control
box indicators flashlng under th~ control of the micro-processor
circuit,
Data switches 80 are also connected to the input multi-plexer
circuit ~2. These switches are important to a~sure sygtem versatility.
8efore in6tallation, the system may be used on any kind of machine, such
as excavatorfi and conuentional tslescopic or tower cranes. 8ut these
machlne~ all have ~pecial characteristics that must be known by the
contrcl circuit to assure proper operation. These switches are then
progr~mmed at the time of installation to insert in the system data that
~l _
1~';"7'~5~
are p~rtin~nt to the ty~ nf mechine it i9 to be edapted to. The nature
of the~e data will he di~cu~sed in the software description.
A 12 V.D.C. powe~ supply i~ required for energiz~ng the
indicators and relays of the system. This may be provided directly from
the batt~ry of the machine when ~uch battery i~ 12 V.D.C. However, when
the bettery of the m~chine is a 24 U.O.C., ~ regulator ~2 i~ connected
to such 24 U.D.C. battery for providing the requirHd 12 U.D.C. A S
V.O.C. regulator fl4 i~ connected to the output of the regulator ~2 or to
the output of thn 1~ V.D.C. bettery of the maehine for providing suitable
voltage for the nperation of the micro-processor circuit.
Iigure 9 i~ e schematic diegrem of the input multi-plexer
circuit. It hAs two ~tages. The first is an ;nput interface 86, consisting
of well-known circuits, adapted to reshape the input signals frpm tha
various ~ensor~ and control and data switches to make them compatible
with the micro-proces~or circuit. The input signals are separated in groups
of four by the input interface 86 ~nd fed to a set of eight 4 to 1
chennel selectors aa. For each group of four, only one input signal
at a time is connected to the data bus going to the micro-processor
circuit. The ~election is made via thfl control bus from the micro-
processor circuit. Thus, the micro-processor can "~read" four ~-bit data
word~ (32 input ~ign~ls). A fifth word Or 6 bits can be read ~ia six
three-state buffers (HLX 3-~tate buffer 90) connected on the data bu~.
Flgure 10 io a schematlc dlagram of ths output clrcult. The
data bus from the mlcro-prooessor clrcuit is connected to elght well-
known latches 92 acting like small memories. Under control of the control
bus of the micro-proce~sor circuit, the 13tches will store the proper
output signal~. These sign~ls ere then bu~fered by wsll-known output
~mplifi0rs 94 to drive the control box and ~xternal indlcator~ and a
~et of relays M,L and fl. A special feature of the relay output is thst
3û thers is an interlocking circuit on both the coils and the contact~.
This is to avoid two or three contacts to be actuated at the some time,
8 situation that must not occur for safe operatlon but could occur lf
a failure happen~.
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.11'i~'79S9
,7elay~ and ~ ar~ u~d to operate the bloGking ey~tem.
For most applicatlons~ only the ~ tmain) relay ~8 used. It operates
sithr~r a main valve or an electro-mechanlcal device, dependlng on
the typs o~ ma^hinQ~ ln order to allow the operator to manoeuver the
machlne. As a m~tter of fact, the sy~tem 1~ wired in such manner thet
the ~slay M arld the hy~r~ulic, pneumetic or slectro-mechanlcal
component actuated by it must be operatsd, or "alivent to enable the
operation of the machine. This i9 ~n lmportant s~fety faeture; if
there is ~ power f~ilure, or brsak in a wire, etc., the relay ~ i8
releaRed snd the ~anneuvers are blocked.
Also, a certaln number of machinefl are ~free swing", which
mean~ that, when the main valve is relQased 'n block the mschine
controls, there is no sufficiHnt break on the swln~ motor to stop
rotation of the machine, which 18 a very unnafe situPtion. The
machine can continue to swing and hit sn obstacls.
The purpose of the L ~left) and R ~right) rslays i8 to force
ths rotatlnn ln the opposite dlrectlorl up to ths point when the
machine 19 stoppedl This mattsr wlll be dlscussed further ln the
software de~cri~ion.
~0 Concerning the blocking sy~tem, it i~ importRnt to note that
on most hydrnlJllc mAchlnes, lt ;ts possiblq to block the manoeuvnr~ by
introducing a ~m~ll valve (or set of valve~ in the hydraullc syAtem
whlch R~si3t~ the power systsm, instead o~ us~ng a large valve in
the power sygtem. Thi~ allow~ A eimpler snd much le8~ expenslve Ins~tal-
lation.
flgure ll is a schematic dlagrAm of the failure det~ctor.
The principle of operatlon of the micro-procs~or consi~ts ln executing
a flst of instructions ln sequence (ths prnyram). ~hen the pro~ra~i
loop is ~xecuted, the processnr get~ back to the first lnstruction
and executes the same loop agaln, and 80 nn. Each loop takes a certain
tims of execution, in tha nrder of a few mlllls~rondn. Thus, the
program loop oontaln~ the neces~ary instructions to generat~ a pulse
at ~ certain output and, durlng normsl operatlon, thls QUtpUt will
.li~7'7~59
generate A contlnuous pul~e train. A~ ~hown in ~lgurs 11, this
pulee tr~in i9 u~d to trlgger end re-trigger a one-~hot clrcuit 96
to mslntain it~ autput .ln ~ certaln etate. In this manner, lf
somethin~ goe8 wrong in the micro-prncessor cir~uit, the pulse train
will ~top and the one-shot clrcult will ~all in the ~ailure state.
This wlll reRst the output circuit 74 nnd cause the maln reley M to
releaYe and block the menoeuvers. Al~o, the micro-proceesor clrcuit
wlll be reeet ~n an ~Ittempt to start again the program loop.
the ehove-discloeed hardware is controlled by the progrsm
stored in the reAd~only-memory (R0~) 66, The program, os ~oftware,
i9 the set of inetruction~ whioh enables the mlcro-oroces~or circuit
64 to achluvs all the functions that are neceeRary for the good operatlon
of the system- ~hese functions ~re Re fQllDWY:
a) InD~u~_3~glD~ - The input reading routine controls the lnput
multi-plexer 72 to reech all the input in~orma~ion coming
~rom ths sensor~ 24, 26, 28, and 30, the control switchoe
in control box 22 and the data switches H0. The lnpot
informetion ie then etored ln the RAM 68 for further uee.
b) 5~ sel~ction - This routine wlll tak~ the data on eome
of the data switche~ a~ to determlne whether the syetem
is used on an sxcavator, a conventional crane, a teleo-
coplc crane or ~ tower crane. Thn nption data will be u~d
furthe-. to makH bsanches ~t th~ propflr routlnen or to lnter-
pret the data in tho proper manner, becau~e eome dif-
ferencea among the machinee will lnvolve diffurences ln
the data treatment.
c) Limit aelection - ~ep~nding on the typa of mschine and the
mode o~ ope-etion, th3 type of llmit to be stored in
the RAM memory 6~ will vary. Thie routine uee~ the option
data ~nd th~ selectos switch 51 ~n the control box 22 to
e~t tho propor bronches and data treatm~nt to b0 done.
In thls manner~ it 1B po~slbla to use the ~ystem in ~lmoot
any ~ltuation in the ~ield.
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11~7'~959
d) ~imlt r ~r~ing - nfter th~ llmit Re~ectlon ha~ been made,
the limit~ are automaticslly recorded. The limits wlll
e~sentlally be the maximum position datA recelved from
eflch sensDr 24, 26 or 28, or 8 comblnatlon o~ them.
For example, the maximum vertical position o~ the boem can
be recorded alone. Or on ~ telsscopic crane, a comblnation
of the boom angls and ths boom length allows the calcul~tion
of the limit poeltlon of the boom cable. Thi~ will be further
di~cu~ed ln this chapter.
~) ~uPfer zo ~ c~]culatiDn - When the limit data ar0 stored in the
RAM !~emory 68, a calculatinn i~ made to dstermine the limits
of a c~Jrtaln burfer zone whlch i~ used to warn th~ operqtor
of the apprnach of a llmlt In ordsr to allow him to react
accord1ngly. The width of the buf~er zone can be programmed
durlng in~tallationj-by means ot the data switcheR 80, and
thus can have di~fsrent v~luss, depending on the applicatlon.
~) _urrHnt po~iti~aLJ~g~ ___n - The current position of the machine
i~, of cour9~, continuously calculated from the lnput da~a
coming ~rom the sensors 24, 26,and 2~. The slgnals coma
in pul~s or pul~e traln~ ~nd must b~ intsrpreted ~lth regard
to a ref~rnnce determined by the processor. The ol~nal~
are flr~t flnalyaed to detsct a tal~e condltlnn, whlch would
re~ult from A dBfeCtiVB component. Then ~ net of countere
storhd ln the RAM 6~ are incrHmented or decrsmented, depend-
ing nn thH dlr~ction o~ the movement. The state o~ thPse
counters iB ths curr~nt posltion o~ the machine.
g) ~Hl~e~c~Qic boom l~ng~ mE~Qge~ - On a tel~scopic crane~
th~ current posltion le not determlned only by the angls
of the boom but al~o by it~ lHngth, which may ~ary during
operation. So the current poaition calculation muct take
into account the angls o~ the boom with regard to thH
hori~ontal, thH initial boom length and the boam length
incr0a~s. For a "wall~' po~ltion ~to be d~fined later), th~
.li~7'795~
formula i~ the lullowing:
P -- (L-~l) cosA
Where: P = position of`the boom
L = in.itial boorn leng~h
1 - boom langth .increese
A = boom angle relat.iv~ to the h~izontal
A i9 in degrees. P, L and 1 havH the same arbitrary unitt
thn mo.st convonient that h~s ~aen ~ und to ~implify the
dasign of the system. Tha value of L i~ datarmined during
installRtion, via the data switches.
For a "cailing" position (to be defined later), the formula
is: :
p _. ~b ~ 1~ cos(90 - A)
As it will be described later, the operator can program the
system for "wal}" or "ceiling" limits~ depanding on the
position of tha obstaclr.~s.
When pro~ramming the limits, it is thus the maximum value
of P that is stored as the llmit. And wh~n ths conparison
i3 m~de betwuan the current position and the l.imit, the
boom langth/boom angle compansation ls automatically ma~e~
for a "wall" limit, if A increases, 1 can increase b&~ora
reaching th0 ~ms P linlit. For a "ceiling" limit~ if A
increasas 1 must decrease to stay in the limit,
h) Zone calculation - ûnce the po~ition limits~ and ths buffer zone
____
limi.ts are known, the range of the machina can be divided
intc threa zones: a working zone, a buffer zonq and a
forb~ un zone. By comparison of tha current position with
the orerecorded limits, it becomes easy to determine in
which zone the machina stands.
i) ~ - As mentioned in tha hardware descrip-
tion, it may be neca~sary to usa the L or R relays to
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11 7 7~59
stop the rotat.ion of the macllinH, In order to get a smooth
nperc~ on, il. Jecomes necessary to know the swing speed
of t;~e machine. Thus the L or R relay will be operated
only if tha swing speed is greatsr than a certain preset
valus. This value may be prograrnmed on some of the data
switches ~0. Also, if the L or R relay is operated, t
will rel~ase automatically when the swing spefld drops
under the preset value.
This routine calculates the swing speed by counting the
input pulses coming from tho horl~.ontal position sensor
26 in a certain period of time~
j) out~UE_aE~ The output routine takes the rQsults of the cal-
culations and sets the state of the outputs following the
zone and the position of tha selector switch 5 1. When
the output signal is properly set, it is directed on the
data DUS to the latches 92 in tha output circuit 74 ~ia
the control bus. This will.operate the indicators Ll~
L2, L3 and A of the control box 2~ the external indicstors
34 and 36, and the blocking system 32 via the ouput relays
M, L and R.
k) _i ~ re - As the system is a safety device~ it must
reMct safely when it is defective~ For thie reason~ the
systen hardware is designed so that tha input data i9
coded baFore bsing "read" by the micro-procesaor circuit 65
In this manner, if a component fails, either in a sensor 24,
26 or 2~ or in ths junction box 20 or the control switches
51, S2, S3 and S4, it will induce a wrong code that will
be detected by the software. As a result, ths program
wi11 b.lock the ~anoeuvres and give an indication of failure
to cha operator.
The program also generates a pulsQ train that can be detected
by the failure detector circ~it. If something gaes wrong in
ths micro-processor circuitt the program will no mora be
_ 15 -
11~7t79S9
exscuted and the pulse train will stop. This will also
block the manosuvres (see the hardware dsscription of
figurs 11).
1) Machine displacement - Whsn the machine moves on the ground, a
signal is givsn by the displacsmsnt ssnsor. This signal
i8 used to modify the limits that could vary with regard
to the position of ths machine on ths ground. Ths limits
are not corrected but modified in such a mann~r that the
operator will stay in a secure situation.
Ths range controllsr can bs operatsd following differ0nt
modes, depending on the situation of the machine with regard to the
surrounding obstacles. In ~act, the system acts in such a manner that
in some instancss a virtual ~csiling" is simulated over ths machine
and the controls of the machine are blocked whsn ths boom reachss a
csrtain angls sensud by the vertical position sensor 24, no matter
the horizontal position. In othsr instancss, it i8 a "wall~ that i9
simulated in the sams mannsr~ in front of ths machins.
On the other hand~ ~sids-wall3~ may be simulatsd by using
ths horizontal position aensor 26~ so that the swing motor o~ the
machins will Qtop at certain horizontal positions.
ThH purpose oP the range controller is to place thsse
"ceilingn~ "wall" or "side-wallsn, or a combination of them~ between
the nbstacl~ (s) and the machine. Ths different mod~s are~
a) Mode 1 - Such mode i~ used to program a "ceiling~ limit only.
With the selector switch Sl on Pl~ the operator mo~es the
boom upward, up to the acceptable limit~ before coming
back in ths working zDns. Result~ a ceiling limit is
sensed by vertical position ssnsor 24 over 360 of rotation.
Such c0iling limit is storsd in the RAM msmory 68.
b) Mode 2 - Such mods is used to program "side-wall~ limits only.
With the selector switch on Pl~ the operator rotates the
machine up to the acceptable left and right limits~ before
- 16 -
5'3
coming back in the working zone. Result~ no ceiling limit
in the opening but "side wall" 11mits on both side3
allowing no access outside such limits. Such "side
wall" limits are likewise stored in the RA~ memory 68.
c) ~ode 3 - Such mode is used to program a "ceiling" limit with an
opening. With the selector switch on Pl~ the operator moves
the boom upward and rotates the machine left and right up
to the acceptable limits~ before coming back in the working
zone. Results no ceiling limit in the opening and a ceiling
limit outside the opening.
d) Mode 4 - Such mode is used to program a variable "ceiling~ limit
over a certain angle of rotation. With the selector switch
on P2~ the operator rotates the machine while maintaining
the boom always at its limit~ whatever the limit~ uhich
may vary in whatever manner over up to 360 of rotation.
Result~ a ceiling limit that will vary with regard to the
horizontal position of the machine. If the operator doe~
not cover 360 of rotation, there will be no access in
the remaining portion of the range.
e) ~odss usino a "wall" limit - When using the preceding mode~ a
"ceiling" limit i8 programmed because the processor storea
the most "upward" value reached by the ~ertical position
sensnr. However~ when the system is used on a orane for
exemple~ it is often the most "downward" value that must
be stored as the limit~ ag the wire of the crane may touch
an obstacle placed in front of it. This mean~ that the
limit becomes a ~wall" limit. It is possible for the
operator to select thH "ceiling" or "wall~ operation by
means of a switch.
In the case where operator selects the "walln-oper~ti4n~
he can use mode 1~ mode 2, mode 3 or mode 4 in the same
manner as previously described~ but with a "wall" instead
of a "ceiling" and move the boom downward instead of upward.
_ 17 -
li~7'7959
f) ~ - This mode is used to work without any limit. As
mention~d earlier in the hardware deacription~ the blocking
system components mu~t be ~alive~' to enable the operation
of the machine, which means that the system must be "on".
Thus, when no limit is required~ the manual mode can be
used. The selector switch 51 is on ~AN.
g) Manual mode cancsllation - When a job asks for a high leuel of `
security~ it is possible for the foremen to be ~ure the
operator will use the system and program it with limits.
To do this he just hns to operate a key switch 53 provi-
ded with the system, and remove the key. Thi~ switch
cancels the manual mode, which means that the machine
cannot be operated unlsss limits are programmed.
h) Raturn to tha workinq zone - When the operator reaches a limit~
all the manoeuvres are blocked. In order to come back
in the working zone, the operator can put the selector
switch on MAN or use the return switch s4. This return
switch gives back the controls to the operator for the
time he operates it.
The visual lights Ll~ L2 and L3 ano the audible indicator
A give the operator all the necessary information concerning the mode
of operation and the current zone (working~ bufPer or forbidden).
They also indicate if a failure has been detected.
In order to implement the functions which were described
in the hardwar~ description, it is possible to use many types of
circuits and components. Those that have been selected are all
simple, standard and known circuits and components so that there is
no need to describe them in further detaii.
Also, all the components that could be inappropriately
a~fected by the environment are pre~erably pratected by, ~or example,
solid metal boxes, shields~ sealing compound~ heat sinks~ insulating
materials, and so on.
., .
